1. Field of Invention
This invention relates generally to toy gas-fired missiles, and more particularly to a toy gas-fired missile and launcher assembly in which the explosive mixture for propelling the missile is derived from colonic gas discharged by the operator of the toy.
2. Status of Prior Art
Flatulence is the accumulation of excessive gas in the stomach or intestine. Because flatulence may be socially embarrassing, it is one of the most common complaints encountered in medical practice. Although a number of factors have been implicated in its pathogenesis, sometimes no cause can be found and it may therefore prove refractory to treatment. Thus, serious discussions of flatulence have led to little more than home remedies, largely empirically derived. Only in the last three decades has there emerged a science of flatology (Price, et al., 1988; Danzl, 1992).
A number of variables determine the volume, composition and frequency of flatus (Fardy and Sullivan, 1988). These include age, heredity, stress, diet and antibiotics. Normal individuals eating a typical diet produce 400 to 1,600 ml of flatus per day (Levitt, 1971). The composition of flatus varies dramatically among individuals. Five simple odorless gases are their major components. In order of decreasing prevalence in normal individuals, these are nitrogen, hydrogen, carbon dioxide, methane and oxygen (Van Ness and Cattau, 1985).
The odor associated with flatus is due to hydrogen sulfide, skatole, indole, volatile amines and short-chain fatty acids. These substances are detectable by olfactory neurons in concentrations as low as 10 parts per billion (Levitt and Bond, 1970, Boucher, 1980).
There are four mechanisms of intestinal gas production. The least significant contributor of intestinal gas volume is the diffusion of gas from tissues and vasculature to the bowel. Under normal conditions, this constitutes only a few percent of the total volume, and the primary component is carbon dioxide (Danhof, 1968). Another more minor component of gas production is from the acidification of bicarbonate in intestinal secretions. The primary gas produced in this manner is also carbon dioxide, most of which is absorbed in the upper gut (Bouchier, 1980). Aerophagia can be a major source of intestinal gas. The percentage of nitrogen in flatus increases with air swallowing (Rider and Moeller, 1960), and postprandial bloating secondary to air swallowing is exacerbated by fat indigestion, which delays gastric emptying (Polish and Kadish, 1968; Van Ness and Cattau, 1985).
The least understood mechanism of intestinal gas production is that from bacterial fermentation in the colon (Friedman, 1991). Fermentation of indigestible polysaccharides by colonic bacteria results in dramatic increases in hydrogen production and flatus passage. In legumes, for example, raffinose and stachyose have been implicated as the major oligosaccharides that provide the substrate for colonic bacteria. Cellulose, which is the main component of the tough outer coating of beans, also is nondigestible and provides a similar substrate (Van Ness and Cattau, 1985).
Aside from occasional caveats found in textbooks concerning the dangers of electrocautery and the subsequent explosion of the colon during surgery (Levitt and Bond, 1978), or anecdotal accounts of flatus ignition, there is little scientific discourse on the combustive properties of flatus.
A recreational activity practiced by some individuals is ignition of one's own flatus. This is performed by using a lit match or candle, or a cigarette lighter. So widespread is this activity that there are web sites on the Internet devoted exclusively to explaining proper lighting techniques.
A major drawback of this popular practice is that it usually involves the hazardous coupling of fire, combustible gases and inebriated participants. Reports of serious burns to body parts are not uncommon, this being especially true when the participants remove their clothing.
References:
1. Bouchier, I. A. D. (1980) The Practitioner, 224;373-377. Modification, Garland Publishing, Inc. N.Y. PA0 2. Danhof, I. E. (1968) Ann. N. Y. Acad. Sci. 150;127-140. PA0 3. Danzl, D. F. (1992) J. Emerg. Med., 10(1);79-88. PA0 4. Fardy, J. and Sullivan, S. (1988) CMAJ, 139(12);1137-1142. PA0 5. Friedman, G. (1991) Gastroenterol. Clin. North Am. 20(2); 313-324. PA0 6. Levitt, M. D. (1971) New Engl. J. Med., 284;1394-1398. PA0 7. Levitt, M. D. and Bond, J. H. (1978) in Intestinal Gas and Gastrointestinal Disease, J. S. PA0 8. Polish, E. and Kadish, U. (1968) Ann. N. Y. Acad. Sci., 150;67-74. PA0 9. Price, K. R., Lewis, J., Wyatt, G. M. and Fenwick, G. R. (1988) Nahrung, 32(6);609-626. PA0 10. Rider, J. A. and Moeller, H. C. (1960) JAMA, 174;2052-2054. PA0 11. Van Ness, M. M. and Cattau, E. L. (1985) Am. Fam. Practioner, 31;198-208.